Pressure actuated switch



Filed June 17, 1932 fly n0 4 INVENTOR CHARLES JARDINE BY HIS ATTORNEYS gfi aww c I Patented Mar. 13, 1 934 r v UNITED STATES PATENT OFFICE PRESSURE ACTUATED SWITCH Charles Jardine, Toledo, Ohio, assignor to Moto Meter Gauge & Equipment Corporation, Toledo, Ohio, a corporation of Delaware Application June 17, 1932, Serial No. 817,911 7 Claims. (01200-83) This invention relates to pressure actuated The casing 10 preferably comprises a base porswitches, and more particularly to devices of tion 28 and an annular wall portion 29. A comthis character adapted to make or break a cirpressible insulating gasket is interposed becuit when the pressure to which the device is tween the rim of the diaphragm and the base por- 6 responsive varies from a predetermined setting. tion 28 outside of the chamber 12. The dia- While the invention is of general application, it phragm 15 has rim portions 32 turned up to inis particularly useful in connection with the lusure contact thereof with the wall portion 29. brication system of an internal combustion en- When the parts are assembled, the rim of the wall gine, for energizing a circuit including an alarm portion is crimped or spun over the insulator 14, such as a signal light, when the oil pressure and retains the gasket 30 compressed. falls below a satisfactory operating pressure. A recess 33 is formed in the face of the insula- Objects of the invention are to improve the tor 14 adjacent the diaphragm and aligned with construction and operation of devices of this the chamber 12. The base portion 28 has a holcharacter, to render the same inexpensive to low threaded boss 34, which is screwed into the manufacture, convenient to install and adjust, source of pressure, so that the pressure to which and otherwise better adapted for the purposes the switch is responsive is supplied to the chamset forth. ber 12.

' In the drawing, the single figure is a cross- A terminal 35 is connected to the contact 16, section through a pressure actuated switch acby a screw 36 passing through the same and cording to the preferred embodiment of the presengaging the outer end of the threaded bore 23. cut invention, it being understood that various This terminal connects the contact 16 to the modifications may-be made therein without desource of electrical power and the circuit to be parting from the scope of the appended claims. controlled by the switch, including a ground, and

The switch comprises a casing 10 having a the boss 34 is grounded so that the circuit ispressure chamber 12 and an insulator 14, a diabroken only by the contacts 16 and 1'7 being sepaphragm 15 being mounted between the insurated by the action of the diaphragm. lator 14 and the pressure chamber. "A fixed con- From the foregoingdescription, it will be obvitact 16 is separated from the diaphragm 15 by .ous that when the pressure in the chamber 12 the insulator 14, and a movable contact 17 passes exceeds the pressure to which the spring 25 is through the insulator 14 for actuation by the adjusted bythe plug 24, the diaphragm moves phragm 15. upwardly, forcing the stem of the contact 1'7 up- The insulator 14 is preferably a molded block wardly and thereby lifting the head thereof out of phenol condensation product, and the fixed of enga men w h the rim of the Wa1118- when contact 16 is preferably a hollow metal cylinder the pressure falls below the desired critical sethaving an end wall 18 embedded in this block ting, the spring 25 forces the head of the contact and provided with an aperture 20. A passage 17 into engagement with the wall 18 and thus 22 is formed in the insulator 14, aligned with the completes the circuit to the alarm or other device aperture 20. controlled by the switch.

In the form shown, the movable contact 1'7 The diaphragm 15 may be constructed of very has a head inside the bore 23 ofthe fixed conflexible material, and the spring 25 may be so tact, and a stem passing through the aperture selected or adjusted that the force exerted by the 20 and passage 22, terminating adjacent the diaspring is only slightly in excess of the resistance phragm 15. The passage 22 thus forms a guide of the diaphragm to deflection. With this arfor the stem of the movable contact 17, and the rangement a very small pressure of the order of aperture 20 is provided with sufficient clearance 5 to 10 pounds per square inch on the underside to cause the contacts to engage only at the outer of the diaphragm causes an initial movement and rim of the head of the contact 17 and the inner consequent opening of the electrical circuit. rim of the wall 18; The diaphragm engages the underside of the The outer end of the bore 23 is threaded to reinsulator 14 before the elastic limit thereof is ceive a threaded plug 24, and a helical coiled reached, so that over pressures of around 500 to spring 25 is interposed between this plug and 600 pounds p sq inch cannot i ju e t e an insulating disk 26 bearing on the head of the diaphragm. contact 17. The plug 24 may thus adjust the I claim: pressure with which the spring 25 resists the 1. In a pressure actuated switch, a casing havaction of the diaphragm 15. ing a pressure chamber, a molded insert in said casing, a diaphragm between said insert and said chamber, a hollow contact having an end wall embedded in said insert and spaced from said diaphragm, and a movable contact cooperating with said end wall and passing through said insert for actuation by said diaphragm.

2. In a pressure actuated switch,a casing hav ing a pressure chamber, an insulator associated with said casing, a diaphragm between said insulator and said pressure chamber, a hollow contact having an end wall associated with said insulator and spaced thereby from said diaphragm, a movable contact having a head in said hollow contact and means actuated by said diaphragm for moving said movable contact.

3. In a pressure actuated switch, a casing having a pressure chamber, a molded insert in said casing, a diaphragm between said insert and said chamber, a hollow contact having an end wall embedded in said insert and spaced from said diaphragm, a movable contact having a head in said hollow contact and a stem passing through said end wall and said insert for actuation by.

said diaphragm.

4. In a pressure actuated switch, a casing having a pressure chamber, an insulator associated with said casing, a diaphragm between said insulator and said pressure chamber, a hollow cylin drical contact separated from said diaphragm by said insulator, a movable contact having; a head within said hollow contact, insulated means in said hollow contact urging said head toward said diaphragm, and means actuated by said dia phragm for moving said head against the action of said means.

5. In a pressure actuated switch, a casing having a pressure chamber, a molded insert in said casing, a diaphragm between said insert and said chamber, a hollow cylindrical contact having an apertured end wall embedded in said insert, a

movable contact having a head within said hollow contact and a stem passing through said aperture and said insert for actuation by said diaphragm, insulated means in said hollow contact urging said head against said wall, and an adjustable abutment for said means closing said hollow contact.

6. In a pressure actuated switch, a casing having a base portion and cylindrical wall, said base portion having a recess formed therein, said cas ing having a passage communicating with said recess, an insulator in said casing, a diaphragm between said insulator and said base portion, a gasket between said diaphragm and said base portion, the rim of said wall being crimped over said insulator to clamp said gasket between said diaphragm and said base portion, a fixed contct spaced from said diaphragm by said insula r, and a movable contact cooperating with s id fixed contact and passing through said insulator for actuation by said diaphragm. o

7. In a pressure actuated switch, a casing having a pressure chamber, a molded insert in said casing, a diaphragm between said insert and said chamber, a cylindrical contact having a longitudinal bore threaded at its outer end and termimating in an inner end wall embedded in said insert and having an aperture therein, said insert having a guide passage aligned with said aperture, a movable contact having a head within said bore and a stern passing through said aperture and slidable in said guide passage, an insuiating disk in said bore engaging said head, a

' plug in the threaded portion of said bore, a compression spring in said bore between said piug and said dish, a screw threaded in the outer end "of said bore, and a terminal clamped between the head of said screw and the outer end of said hollow contact member.

CHARLES JARDINE. 

